1. Field of the Invention
The present invention relates to an optical apparatus, such as a lens barrel attachable to a camera body, and a lens-integrated camera.
2. Description of the Related Art
A zoom lens may cause unexpected zooming in upward or downward capturing and change a composition due to its own weight, when a lens unit configured to move in zooming is heavy or has a large moving amount. When a zoom lens configured to change its overall length in zooming is carried, the zoom lens may cause unexpected zooming, a lens barrel may extend to an object side, and the zoom lens may break. Accordingly, Japanese Patent Laid-Open No. (“JP”) 60-241006 includes an adjusting ring configured to adjust a zooming load and arranged next to a zooming ring, an elastic member held between the zooming ring and the adjusting ring, and makes the zooming load variable by changing a force applied by the elastic member to the zooming ring when the adjusting ring is rotated. Japanese Utility-Model Publication No. (“JU”) 7-49456 engages a forcing unit with a cam groove in an inner circumference of an adjusting ring and makes the zooming load variable by changing the force of the forcing unit applied to a cam cylinder when the adjusting ring is rotated.
A conventional method indicates a zoom state of a zoom lens by a scale printed on the zooming ring and a pointer printed on a non-rotatable member arranged next to the zooming ring. However, in JP 60-241006, the neighboring zooming ring and adjusting ring rotate together and thus cannot use this method. A second embodiment of JU 7-49456 (directed to the zoom lens barrel illustrated in FIG. 5 of the reference), for example, arranges a fixed member (fixed barrel 52) between the cam cylinder (magnification-varying ring 50 connected to the cam cylinder 51) and the adjusting ring (zooming ring 7) and thus can indicate a zoom state (a variable-magnification state) using the above method (in which the scale is printed on the zooming ring and the pointer is printed on the non-rotatable member next to the zooming ring). Nevertheless, a zoom lens barrel illustrated in FIG. 5 of this reference requires a space for the forcing member (wave spring 10) on an end surface of the cam cylinder in an optical axis direction, and the entire product becomes long. In general, the cam cylinder is longer than the zooming ring in the optical axis direction. When the forcing member is provided on the end surface of the cam cylinder in the optical axis direction, the entire product becomes longer in the optical axis direction by the length of the forcing member. Moreover, it is necessary to locate the cam cylinder near an outer surface of the product.